Anorak stuff: pressure-velocity relationships

In a slack moment this afternoon I have graphed up pressure-velocity data for 2 common cartridges with sensible (cast) bullet weights to see what it looks like, and I think the results have more than just interest value.

I used the 3rd edition Lyman cast bullet Handbook, and picked a 308 Winchester with a 151 grain bullet and good old 9 x 19 mm at 121 grains. You can certainly see at a glance what the various powders do, and in the 308 example there is a clear-cut difference between the pistol/shot gun powders and the rifle powders. Another interesting one to look out in particular is the difference between unique and Herco in the 308.

The results are included as two attached Excel files.



It's just interesting to see how the slope of the graph is different (or mostly not) for various powders, and lets you see at a glance which powders are suitable for a given velocity range.

If I get some time and have the inclination, I might do charge weight versus velocity, and charge weight versus pressure.

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